# Competency Based Questions Chapter 8 Light, Shadows and Reflections

Hint: Distinguishes objects based on the emission of light by them and visibility through them.

Question.1. The image shows three objects made of glass.Which object has the ability to emit light?

(a) Only P
(b) Only Q
(c) Only P and Q
(d) Only P and R

Question.2. A student is making a model of a garden. He wants to cover the model with a sheet that allows everyone to see through it. Which sheet should the student use?

(a) paper
(b) clear plastic wrap
(c) aluminium foil
(d) cotton cloth

Ans.1. (b) Only Q
Ans.2. (b) clear plastic wrap

Hint: Concludes that there should be a source of light, opaque object and a surface for shadows to form.

Question.3. A student stands in front of a lamp to produce the shadow of his body. The shadow of the boy is formed on the screen as shown.What can be concluded from the observation regarding formation of the shadows?

(a) the screen must be placed in front of the opaque object
(b) the opaque object must be placed behind the source of light
(c) the opaque object must be placed between source of light and the screen
(d) the source of light must be placed between the opaque object and the screen

Question.4. A student has the given objects for an experiment.There are three positions (X, Y, and Z) marked on the table.What should be placed at these positions to form an image on the white cardboard?

(a) X: candle, Y: ball, Z: mirror
(b) X: mirror, Y: ball, Z: cardboard
(c) X: candle, Y: ball, Z: cardboard
(d) X: ball, Y: candle, Z: cardboard

Ans.3. (c) the opaque object must be placed between source of light and the screen
Ans.4. (c) X: candle, Y: ball, Z: cardboard

Hint: Evaluates criteria for formation of shadows and makes judgment about situations like, shadow of an airplane flying at a higher altitude and shadow of a bird flying nearer to the ground.

Question.5. The image shows a hot air balloon flying at higher altitude.What should be the position of the Sun to get the shadow of the hot air balloon at O?

(a) at P
(b) at Q
(c) at R
(d) at S

Question.6. A student learns that the closer the object to the source of light, larger the shadow will be formed on the surface. The image shows the bird flying under the sun and four different position.At which position the shadow of the bird will be larger?

(a) at W
(b) at X
(c) at Y
(d) at Z

Ans.5. (c) at R
Ans.6. (a) at W

Hint: Represents working of a pinhole camera diagrammatically.

Question.7. The image shows a pinhole camera.Where does the image of the object in the pinhole camera form?

(a) at the pinhole
(b) at the translucent screen
(c) on the inner surface of the inner box
(d) on the upper surface of the outer box

Question.8. A student develops a model of a pinhole camera using two boxes as shown. The student put the small box in the big box. He starts observing the object through the pinhole camera but does not get the clear image. What should the student do to get a clear image?

(a) turn the sides of the inner box
(b) make a pinhole in the inner box
(c) paste a tracing paper on the outer box
(d) move the inner box forward or back

Ans.7. (b) at the translucent screen
Ans.8. (d) move the inner box forward or back

Hint: Summarizes the characteristics of image formed by a pinhole camera.

Question.9. A student observes the lighted bulb through the pinhole camera as shown.Which option shows the image formation of the bulb in the camera?

(a) erect image at pinhole
(b) upside down image at pinhole
(c) erect image at translucent screen
(d) upside down image at translucent screen

Question.10. A student observes a tree using a pinhole camera. She decreases the distance between the tree and the camera and looks at the tree through the camera again. The image formed is as shown.What can be concluded from the image?

(a) farther the object, larger the erect image
(b) farther the object, smaller the erect image
(c) closer the object, larger the inverted image
(d) closer the object, smaller the inverted image

Ans.9. (d) upside down image at translucent screen
Ans.10. (c) closer the object, larger the inverted image

Hint: Makes conclusion about the nature of reflection shown by a plane mirror.

Question.11. The image shows the reflection of a candle.Which statement is correct based on the observation?

(a) plane mirror produces an upright image of the same size
(b) plane mirror produces an upright image of a smaller size
(c) plane mirror produces an upside-down image of the same size
(d) plane mirror produces an upside-down image of a smaller size

Question.12. A student flashed a light from source on a mirror, as shown.In which direction is the light likely to be reflected from the mirror?

(a) towards P
(b) towards Q
(c) towards R
(d) towards S

Ans.11. (a) plane mirror produces an upright image of the same size
Ans.12. (c) towards R

Hint: Distinguish between shadows & reflections.

Question.13. A student makes two setups using a torch and a ball to study

(ii) Reflection of light.

The table below shows some material that was used in creating two setups.Which pair of the given material could be used in addition to the torch and the ball to demonstrate formation of shadow and reflection of light?

(a) Shadow: glass sheet, Reflection: mirror
(b) Shadow: cardboard sheet, Reflection: mirror
(c) Shadow: tracing paper, Reflection: glass sheet
(d) Shadow: cardboard sheet, Reflection: tracing paper

Question.14. The image shows the setup of the reflection and shadow formation.What can be concluded by the observation?

(a) shadow forms when light is blocked by an object, whereas reflection is bouncing of light
(b) shadow forms when light passes through an object, whereas reflection is absorption of light
(c) a shadow forms when the light is blocked by an object, whereas reflection is absorption of light
(d) a shadow forms when the light passes through an object, whereas reflection is bouncing of light

Ans.13. (a) Shadow: glass sheet, Reflection: mirror
Ans.14. (a) shadow forms when light is blocked by an object, whereas reflection is bouncing of light